1. Field of the Invention
The invention relates to a reflector, a receiver arrangement, and a sensor for thermal solar collectors.
A first aspect of the invention relates to a reflector for uniaxially concentrating thermal solar collectors having a panel. Such a reflector is preferably used in linearly concentrating solar-thermal collectors for collecting solar radiation. In this connection, incident sunlight is reflected onto a narrow band, the receiver. The receiver converts the radiation energy to heat energy. A medium transports the heat to the consumer.
Linearly concentrating reflectors are reflective surfaces having a concave curvature in one direction. Depending on their use, the surfaces follow concrete mathematical functions. These applications are parabolic trough collectors, Fresnel collectors, and, with some restrictions, also biaxially curved collectors. In the case of parabolic trough collectors, the surface of the reflector follows a parabolic function. In the case of Fresnel collectors, the function is divided up into smaller segments having the length of the collector, in which sections the reflectors are either planar or have a circular concave curvature.
2. Prior Art
Known reflectors consist either of glass with a mirror coating on the back or of a surface-mirrored material having an obligatory protective layer against weathering influences. Glass reflectors are thermally biased from float glass that is planar, at first, and mirror-coated on the back. Surface-mirrored reflectors are produced by means of the application of a reflector layer to a thin metal foil. This is then glued onto a shape-precise substratum.
In the case of thermally bent glass reflectors, the bent glass has a tendency toward unavoidable waviness of the reflectors. In the case of the surface-mirrored reflectors, the precision of the desired optimal surface shape is determined by the precision of the subconstruction. In this connection, the design effort increases with the precision requirements.